Carburetor



Oct. 31, 1933. F. c. MOCK El AL 3,

CARBURETOR Filed May 21, 1930 5 Sheets-Sheet l INVENTORS Frank C. Mac/c Je fha Mackenzie Mil/er Oct. 31,1933. c. MocK ET AL 1,933,381

CARBURETOR Filed May 21, 1930 5 Sheets-Sheet 2 INVENTORS Frank C Mock Jepf/za Mackenzie MI/er BY I Get. 31, 1933. v F. c. MOCK ET AL CARBURETOR Filed May 21, 1930 5, Sheets-Sheet 3 INVENTORS Frank C Mock By Jepvha MaMenz/ Mil/fr @gct 31, 1933.

I Filed May 2 1930 F. c. MOCK ET AL CARBURETOR 5 Sheets-Sheet 4 N Wk IN VEN TOR Frank 0. Mock By Jepf/m Mack/hm? /*7/'//er Fatented @et 331;, 1583333 UNHTED Parent "@FFHQE.

wearer V oannnanrorr Application "ll/lay 211, 193th.

Our invention relates to carburetors and is more particularly concerned with. the provision of improved means for supplying correct quantities of :fuel under all conditions of operation in 5 airplane use. A I

An object of this invention is to provide a novel type of float to control the feed of fuel into the float chamber so that a positive and uniform supply of fuel willbe fed to the carbureting chamber regardless of the position and speed of the airplane.

Another object of our invention is to provide a readily accessible and cleanable liquid fuel strainer so that same can be easily removed for cleaning from the outside of the carburetor without disturbing any other parts.

Another object of this invention is to provide a novel design of altitude control comprising a main metering jet, a mixture control needle valve with a seat considerably larger than the main metering jet adapted to cut ofi' the flow from the float chamber to themain metering jet. In the side of the needle valve, seat, below the seating point of the needle, we provide an orifice limiting the amount of control obtainable. The size or" this orifice is such as to give the right mixture when the airplane is at or near its ceiling, and "it is thus impossible for the pilot to cut ofi the fuel altogether by improper handling of the control and the control is also much less sensitive at high altitudes. We donot have the needle valve seat in the metering nozzle because we want to preserve an exact sea level adjustment of the metering nozzle. Also, it is desirable to be able to change the sea level adjustment by small but exact increments which is efiected in our device by a simple substitution of metering nozzles of different sizes.

This arrangement of metering nozzle, needle be novel in the art and is highly advantageous in the high altitude operation of airplane carburetors.

Still another object of our invention is'to provide a novel improved means of operating the altitude control needle by a shaft reaching across the float chamber and engaging the slotted upper end of the altitude control needle with an eccentrio-pin. Such an arrangement, afiords a compact assembly with chances for. leakage of liquid fuel to the exterior of the carburetor reduced to a minimum. Both of these points, are of great I valuein airplane operation. as. it reduces vthe space required by the fire risk due to'leaking gasoline. The operating shaft is made relatively Serial No. 454,23t1) (Cita Zilll -MI) large in diameter so as to permit withdrawing eccentric, pin and all. This greatly increases the accessibility anddemountability of the assembly. Also, the altitude control needle valve is threaded into the upper slotted end shank so that the length m of the needle can be adjusted to seat in any desired position of the mixture control lever.

A still further object of our invention is to provide a novel means for the joint operation of the economizer valve and the acceleration pump consisting of an intermediate operating member located in the float chamber space, thereby reducing the areas for leakage from the float chamber and minimizing the entrance of dirt. Also the provision of only one operating connection from the throttle to both economizer and pump insures exact relation of pump travelto economizer valve travel.

A still further object of our invention is to provide a combined manual or automatic means of regulating the main jet mixture control in conjunction with means for reducing the economizer jet delivery in predetermined proportion.

With these and other objects in view which maybe incident to our improvements,our invention consists in the following novel combination,- proportion and arrangement of elements which, for the purpose of explanation, we have illustrated one embodiment in the accompanying drawings.

In the drawings:

Figure 1 is a vertical longitudinal section of a carburetor embodying our improvements;

Figure 2 is a section along the line 2- -2 of Figure 1;

Figure 3 is a section along the line 3-3 of Figure 1;

Figures 4, 5 and 6. are perspective views of detail parts of acceleration pump head assembly;

valve, and fixed or limiting by-pass is believed to\ Figure 7 is a side elevation of the upper half of the carburetor showing acceleration pump operating mechanism; I r

\ Figure 8 is a fragmentary. sectional view of a part of Figure 3 showing an alternate form of economizer construction;

Figure 9 is a side elevation of a modified form of carburetor showing combined manual and automatic altitude control and Figure 10 is a sectional view taken on lines l0l0 of Figure 3.

Referring particularly to Figure 1, the main body of the carburetor is formed in two die cast parts, although obviously this may be varied, these parts having suitable passageways formed therein and provided with fittings to complete 1 lllil the construction. When so formed, the carburetor consists of an upper body portion 1 and a lower body portion 2 which are fastened together by suitable screws 3 (see Figures 2 and 7) with a gasket 4 interposed between the parts, making the carburetor body fluid tight.

In the upper part of body portion 1 is journalled a butterfly throttle valve 5 on a shaft 6, and spanning the joint between body portions 1 and 2 is fixed a Venturi tube 7. A main jet nozzle 8 is fixed concentric with the main air inlet 9 and Venturi tube 8, and has an air bleed tube 10 leading to the outside of the carburetor body 2. Cast integral with the lower body portion 2 is a float chamber 11 in which is located a float l2 fixed to an arm 13 (see Figure 2) fulcrumed on a shaft 14.. Arm 13 carries a pin 15 which engages in a notch 16 in a hollow tubular plunger 17 and this transmits the motion and force of the float 12 to a valve 18 which is fixed in plunger 17 and engages a seat 19, thus controlling the admission of liquid fuel from passageway 20 to the float chamber 12. Passageway 20 communicates with a vertical passageway 21 which in turn communicates with the fuel inlet bore 22 (see Figure 3) to which is attached the fuel supply pipe (not shown). Located in the vertical passageway 21 is a hollow cylindrical screen 23 which is fastened at its lower end into a base plug 2 1 which not only holds the screen 23 in position but also closes the lower end of passageway 21 by screw thread engagement with body 2. Screen 23 is held in vertical spaced relation to passageway 21 by a collar 25 which is attached to the upper end of screen 23 and which has a close slidable fit in the upper end of passageway 21. Collar 25 not only holds the upper end of screen 23 in vertical alignment with passageway 21, but also prevents liquid fuel which enters through bore 22 from passing down passageway 21 without going through screen 23.

Thus liquid fuel which enters through bore 22 tangentiallysto the wall of screen 23 is compelled to flow helically down the inside of the screen, thence through the screen and out by passageway 20. In this way any dirt in the liquid fuel is washed down to the bottom screen 23 and collects on top of plug 24. This plug is readily removable from the outside of the carburetor without removing the air horn so that screen 23 is very accessible for cleaning. The helical flow of fuel over the surface of the screen constantly washes all dirt to the bottom so that screen 23 is largely self-cleaning and only requires removal at infrequent intervals.

The peculiar kidney-shaped float shown in Figure 2 is of particular importance and great advantage for airplane operation. The first floats used in airplane carburetors were spherical as these were least affected by moderate inclinations of the plane, but they had two serious disadvantages: first, they required large fioat chambers both in diameter and height, which is objectionable in airplane use because of the limited space available for the carburetor; and, second, the relatively great distance from the center of the float chamber to the orifice of the main jet nozzle caused considerable variation in the liquid level at the fuel nozzle with various inclinations of the carburetor. The first step toward im-, provement was to shorten the distance between the center of the float chamber and the orifice of the main nozzle by making the float cylindrical with a relatively narrow float chamber having generally straight substantially parallel sides,

said float chamber being disposed with one of its straight sides in immediate proximity to the carburetor barrel, so that there was a minimum variation of liquid level at the fuel nozzle with various inclinations of the'carburetor.

This cured the seconddefect noted above, but not the first, as it still required a float chamber of relatively great height which not only objectionally increased the size of the carburetor but left considerable head room above the float. With such head room, when there is a sudden downward acceleration greater than gravity (as when an airplane is diving), the liquid fuel goes to the top of the float chamber and forces the air to the bottom and the outlet from the float chamber to the main jet is uncovered and the fuel feed interrupted.- The problem was then how to reduce the height and head room of the float chamber without running into the other difficulties noted above. In trying to solve this problem, we first tried a rectangularly shaped float, but found that it was too seriously affected by small inclinations of the carburetor, due to its changing submerged shape as the carburetor is inclined. We then experimented with floats of various shapes and found that only the peculiar kidney-shaped float shown in Figure 2 solved the problem. Its fiat top permitted a substantially shorter float chamber and reduced the head room to the minimum while its cylindrical lower part gave it a substantially constant submerged bulk for the required angles of inclination. This will be appreciated from an inspection of Figure 2. Thus, when the carburetor is level, the liquid fuel line is at Z-Z; when the carburetor is inclined to the right, the liquid level is at X-X and when the carburetor is inclined to the left, the liquid level is at YY.

It will be notedthat in each case, the submerged bulk is substantially the same and the metacenter of the float has not shifted appreciably and therefore the valve 18 is unaffected by such inclinations. It will also be noted that the height of the float chamber and the head room above the liquid have been greatly reduced by the use of our special kidney-shaped float, so that with a sudden downward acceleration greater than gravity when the liquid fuel goes to the top of the float chamber, there is still ample liquid to cover the outlet from the float chamber to the main jet so that no interruption of fuel feed occurs- I Referring to Figures 1 and 3, it will be noted that the liquid fuel leaves the float chamber 11 through an orifice 26'-and flows around the annular groove 27 of a mixture control valve bush- .ing 28 which is secured in a well 29 adjacent the float chamber 11. Bushing 28 has a plurality of relatively large ports 30 which admit fuel to the interior of the bushing, from whence it flows through a central orifice 31, which functions as a seat for the mixture control valve 32, to a main metering restriction 33 below which is a communicating passageway 34 to the main jet nozzle In the bushing 28, below valve seat 31. is a relatively small by-pass duct 35 through which fuel may flow from annular groove 27 to main metering restriction 33 when valve 32 is on its seat 31 and closes the passage therethrou hl i eso sei 0:

oylmrlrioel stem 3? which re-oiprocstes freely through a guide bushing 38 screwed into the top of well Stem 37 carries at its upper end rectangular recess 3% which engages with 2, com oin screw tlireecled into cylindrical head it e mixture control shaft Q2 which rotates in a osizontel cylindrical bore 43 communicating 1 well Bore {i3 is closed at outer end bushing which not serves s "or 42 but which serves to against pressed end. tlius prevent leakage of A d iuel ugli more 43 when carburetor iiii i 37 on. which is secured opesetiiie Arm is ot. A119. 2.) is lielioel operate it from his so t. Well surrounding velve s' "Jl iioli seats lower e 1 on e seal Toy bushingeiicl at s u eml Toe lie lower eml oi sti Zll through 9, and thus prevents to of vs: on st said i is do by operating lever it sioti t "oogli sh t and slot 39 0111 stem is the normally i A-w U is actual eoiiti ol o restricti ada ted cut oejor of the new item tire r to main jet.

mixture control valve rirliicli is always and which oretletermiuerl q entity oi .uel to the mom ie' rv'liei the moisture control valve is closed. This bfy' -"jilSf-i, ts the of mixture co ol cl its is such as to give eorr ot mixtuee tlie is at or near ceiling. The use of such a constantly operi loy-psss makes it impossible for time pilot to accidentally cut oil fuel altogether by improper handling of the control it also makes the control much less sensitive at altitude.

it will notelitliet we do not have the nois tore control needle valve seat in the main meter loeceuse we Went to rve an exsea level adjustment of the main iiieteriug restriction. Also, it is desirable to lee able to @httllgfi the see level adjustment by small but eizoct iri= cremeiits. In the full lean positiorritlte moisture control needle .is fully seetecl. ln full rich post-=- tiori, needle is raised cleer oi its seat. The erouml the needle in the full rich position is. larger than the ores of the main metering re= strictioi'i, so that the size of the main metering restriction determines the quantity of fuel pess= through the instill metering system? it will also be noted. that the altitude control needle is operated by s shaft across the top oi the float chamber and engaging the slotted upper end of the needle valve with an eccentric in; addition, we provide a Memes oessugewav ocliustexi to seat in em? desired position of the mixture control arm &6.

Referring now to Figures 3 and i, the reference iiumeml 53 denotes an acoeletetion cylinder leaving an air-tight integral top to which is fixed cop 54 having a slot 55 in which tits the shank 56 of a stud. bushing 57, the of which fits under the raised portion of cap as clearly shown in Figure 3. Bushing 5? is screvwthteeded into pump oil which in turn is slicleblv mounted; in guide sleeve 59 bolted to top or I ertioii l or bolts it) 1- is e tile iresieie of cylinder 53 Wliicli is slieieolv mounted.

Loosely upon plump 72 Wliioli i is screw-tinsel eel into a loses 73 in tlie '"oottoiL Wall of oliauri== oer Estlltl 72- lies i us geivev it eoriiiiiimicottiie its lower end with trans verse passageway t5 wleic connects with it tlie Tiicsl lieecl t t'oi sturl Piston it lies CEYllZlel sleeve it; which terminates at its top in conical vslve seetlfl meeting with valve lieeoi l? to elose passages '76 when head 77 is con-- testing; Witli seat l9.

Piston ll is tliiust upward lov encircling spring to so that velve seat is is normally lielcl ooriteotlrie with valve head. it smi passageways l6 closed.

operetioi oi" the acceleration pump is olbvl= ous from the foregoing description. When the throttle 5 is oloserL-tlie ports are as shown in Fie= ure 2, the normal iuel level in the fleet chamber 74 communicates at its upper erect with a, plurality oi radial passages-.

Z-Z, Ellld the cylinder 53 is filed with liquid fuel in by preceding suction stroke of the pump. It, now, tlietlirottle is slowly opened, liquid fuel in cylinder 53 will escape through-time restriote-tl opening between cylinder and 1o is= ton ll, es there is only a loose iit between ports. if, on the other hood, the throttle is suoi= tlenly opened, the liquid in cylinder 53 cannot escope test enough as before, and consequently pis ton ll is torcesl clown by the pressure on the lite ulol produced Toy the downward tlmlst oi the evl iorier 53. This uoseets valve 7?, opening oesl6, 74 end 75, and additional fuel is thus eoergeticolly supplied-to the mom iet iiozzie it. As'tlie fuel escapes from cylinder 53, spring so groclumlv returns velve'seot iii to valve 271 encl F fuel is supplied. The features and function of the acceleration pump are covered generically in copending application Serial No. 290,393, filed July 5, 1928, of common ownership with this application, and hence further explanation of this mechanism is necessary. The distinctive feature of the acceleration pump which it is desired to cover and claim in this application is the operating means which constitutes a material improvement over prior devices for this purpose, as will be hereinafter more particularly pointed out.

Referring to Figure 3, it will be noted that cast integral with the bottom of the float chamber 11, near the boss 73, is a similar boss 81 into which is threaded an economizer valve housing 82 carrying an economizer valve 83 which is slidably mounted in the top of housing 82 and seats on a downwardly directed' seat 84. Housing 82 has an axial passageway 85, communicating above valve seat 84 with a plurality of radial orifices which open into the float chamber 11, and at its lower end pasageway 85 communicates through a metering restriction 86 with transverse passageway that leads to main jet nozzle 8. Surrounding stem87 of economizer valve 83, is a helical spring which seats on top of housing 82 and engages the top of stem 87 through an adjustable .nut 88, thus keeping valve 83 normally closed and preventing flow of liquid fuel from float chamber 11 to main jet nozzle 8.

It will be noted that the outer end of arm 67 on acceleration pump stem 58 is in line directly above the top of economizer valve stem 37, so that after acceleration pump stem 58 has descended a certain length of its stroke, arm 6'? engages stem 87 and carries in or down with the stroke of the acceleration pump. This unseats valve 83 and permits additional liquid fuel to flow from fioat chamber 11 to main jet nozzle 8 until accelerating pump stem 58 is raised by closing of throttle 5 a sufficient distance to clear the top of economizer valve stem 87 when .valve 83 seats and cuts off flow of fuel through the economizer valve. The result of this arrangement is that the economizer valve is automatically brought into action every time the throttle is opened beyond a certain point. This point is determined by the amount of space between the top of stem 87 and arm 67 when valve 83 is closed and arm 67 is in its uppermost position (throttle closed), and this space can be varied by bending arm 67 up or down as may be necessary, or by inserting additional washers between arm 67 and the bottom of stem 58. r From the foregoing description, it will be seen that'we have provided a joint operation of the acceleration pump and economizer and that this joint operating member is located inside the float chamber, thereby reducing the areas for leakage from the float chamber and minimizing the entrance of dirt. Our operating arrangement also insures an exact relation of the pump travel to the economizer travel.

In Figure 7 we have illustrated an alternative and preferred arrangement of the economizerand altitude mixture control valve wherein a passageway 89 is provided from the well between the mixture control valve seat 31 and metering re striction 33 to the space in economizer housing 82 above valve seat 84. As this well is kept filled at all times through by-pass 35, the economizer is fed from this source'instead of direct from the float chamber as in Figure 3. When valve 32. is closed and valve 83- open, the feed through the economizer is limited and controlled by the size of the by-pass 35 because by-pass 35 is smaller than metering restriction 33 and the combined areas of metering restrictions 33 and 86 are much greater than by-pass 35. However, as valve 32 is opened,,the combined areas of bores 31 and 35 are greater than the combined areas of metering restrictions 33 and 86, so that with valve 32 open, metering restriction 33 governs the normal feed to main jet 8, while metering restriction 86 governs the supplementary feed of the economizer when valve 83 is open.

In the arrangement of Figure 3, with the ordinary air-cooled engine carburetor setting, the main metering jet 33 at sea level delivers about of the fuel and the jet 86 about 20%. As shown in Figure 3, the altitude control is only on the fuel supply to the main metering jet 33. At a height of one-half atmospheric density, about 17,000, the flow through 86 will decrease about as the square root of the density, or to 15% of the total ground flow. At the same time, without correction, the flow through 33 will decrease to 60% of the total ground flow. We would desire about 50% or actually 45% of the total ground fiow andusing the altitude control of Figure 3, we would have to cut down the delivery through 33 to 30% of the total ground flow, so that this, plus the uncorrected flow of 15% through 86, would equal the 45% just specified. In other words, at this altitude the fiow through 33 would be twice that of 86, whereas on the ground, it is four times. This would mean that at 17,000, with the altitude control so set, if the throttle were closed to a point where valve 83 seated, the mixture would immediately become one-third leaner than with it unseated, which is much too large a step of graduation. The arrangement of Figure 8 overcomes this diniculty because the altitude control operates jointly on the flow through 33 and 86. As a matter of fact, the additional effect of operating the valve 83 becomes less as the effective area of the ori fice 31 is decreased by use of the altitude control, which is just what is desired.

The advantage of the foregoing arrangement is that the economizer action is associated with and modified by the altitude mixture control. This is desirable as the amount of economizer action should be reduced in proportion as altitude is gained. Otherwise, with a constant economizer feed, its proportionate effect at high altitudes is greater and a point is reached when over-enrichment results from economizer operation.

In Figure 9 we have shown an alternative automatic arrangement for the altitude control with regulation of economizer action. In this form of carburetor the construction of the mixture control and economizer valves are the same as in Figure 3 except that valve stems 32 and 87 are carried up through liquid-tight holes in the top of the float chamber and the economizer valve is lifted to open instead of being depressed as in'Figure 3. In order to raise the economizer valve with the openingof the throttle, we have provided a cam 90 fixed on the end of the throttle shaft 6 and engaging a roller 91 on a rocker arm 92 which is pivoted on a floating shaft 93 attached to one end of an operating lever 94. The other end of rocker arm 9 is forked and engages the under side of an adjustable nut 95 threaded on the end of economizer valve stem 8'7. As throttle 5 is opened, cam 90 depresses the roller end of arm 92, which raises the forked tieparting from the scope aesase end of the arm and the valve stem 87, thus opening the ecouomizer valve.

The cam pin ill which engages in the recess 39, instead of being carried on the end of a rotatable shaft, as in Figure 3, is here iixecl to lever 9e and serves to move valve'stem 32 up and clown as lever 94 is oscillated about its eccentric pivot $6. The shaft 97 of the eccentric 96 is jourualell in a plu rality of cars 98 integral with body l, and is rotated by a manual control lever 99 operated by a control from the pilots seat (not shown) and this shifts the axis of oscillation of lever Q4. On the other side of eccentric so, lever 94 branches into two arms ice and lill which engage respec tively a s rin m2 and an aneroitl bellows "r03. Bellows 103 opposes the action of spring 102 and permits it to oscillate lever 94; only as the bEllOV-IS is lengthened and shortened by atmospheric air pressure, Bellows 103 is anchored at its bottom belt 104- aiicl nut lilo engaging" housing loo which is boltecl to body l by one of screws 3 and, a sc ew 10"! tapped into the uccler side oithe iolcl flange on booly l. m2 s adjustable seat lot screw-threaded ihto hous= loll.

e operationthis mechanism is (Bill the foregoing description, As altitude "led, the diminishing atmospheric elts bellows log to allows SEllil'lfi 31% tooscillate lever 94 about its eccentric depressing oin ill, closing valve 552, and lowering shalt 93 lowers the fulcrum o economizer arm 92, d inishing e throw of the r i c l till operates on the roller eiicl rcls, this climuiishes the ecoiioi Figure also, ecoiicuiizer needle valve the top afloat chamber to vent this chair, ber during normal operatic to gireveiit escape of liquid fuel when the carburetor is verted.

Although we have illustrated and a preferred embodiment our invention, we avieee that modifications and changes can be made therein by thososl lied in without the invention as slefihecl in the appended clams; we do not wish to be limited. in these respects, or otherwise than by the terms of the appended claims, \7

We claim: l'. in a carburetor, a float having gen straight substantially parallel Walls, a submerged fuel outlet port, and a semi-cylindrical izloat nearly submerged in sairl chamber, whereby when said chamber is inverted the depth oi submergence oi said port is substantially the same as when said chamber is in upright position.

:3. iii a carburetor having a nozzle, float chamber rectangular in vertical iore-and-ai't cross section, and a semi-=cylimirical float extemllug in a fore-ancl-aft direction in saitl chamber, saicl iioathaving straight parallel sidesvvhereby there is a minimum variation of fuel level at said metering restriction adapted to reduce the flow l raising is delayed to a greater throttle caching,

nozzle with lateral inclinations of said carbu rotor, and. said float having a semi-cylindrical bottom whereby its liquid displacement is substautially the same with moderate fore and aft inclinations oif'said carburetor. all

8., iii a carburetor, an altitude mixture control device, comprising a metering restriction of calibratetl size to pass desired, mixture proportions of fuel at sea level, a valve in series with said of liquid iuel through saicl metering restriction as altitude is gained, and a toy-pass around saicl valve of calibrated size to give clesireol mixture proportion at highest operating altitude when valve is closed. v

l. In a carburetor having a jet nozzle, altitude mixture control device comprising a metering restriction goveri ing the normal flow of liquid fuel to said nozzle, said metering restriction being calibrated to the desired mix- @o ture proportion of liquid fuel at sea level opera tion, and, means operable from the operator's position to chance the sea level adjustment of said restriction by exact calibrated. increments. loclri a carbtu'etor having afloat chamber, as ucle control device comprising an operating shalt joturlalecl across the top of said float chau her having on one cool s eccentric cam of the eccentricity of saicl cam a":

be removed a usuafror the carburetor v," disturbing any other ts thereof.

carburetor, altitude mixture 0011- Bill; trol valve controlling -e main. supply to the carouretor, an auxiliary fuel supply valve and tic means for modifying the oper said valves in proportion to change in titude of the carburetor.

a carburetor, an altituile mixture cori trol value c i trolliiig the main supply to the carburetor, an auxiliary ruelfsupply valve, and atmospheric pressure responsive means for autoroaticallyoperating said vaves with changes in altitude of the carburetor,

8. carburetor, an altitude mixture con trol valve controlling the main supply to the carburetor, an auxiliary fuel supply valve and. a combined manual and automatic means for 2 operating said valves, V

9. lo a carbiu etor having a throttle, an econo ruizer valve, means for operating said valve from. said throttle, and means for automaticallymodithe action of said operating means with changes altitude of the carburetor.

lo, a carburetor, a float chamber having generally straight parallel walls and a flatcover, a money-shaped float nearly submerged in said chamber, a fuel passage having a submerged fuel outlet port in the chamber side Well, said float having its upper side adjacent the cover whereby when said chamber is=inverted the depth FRANK c. lVlOCK. Juicers MACKENZIE a. 15s

A: i all eturuieuru utt euiiuteriuu.

em Nu. 1,933,331. 1. 1 @ciubet 311, 11933.

{FRANK e, ueeit, e11 At.

it it; hereby eertiifiec] that errur appears in the printed speeiiieatiuu ui tine uiouve numbered patent requiring eurreetiun as iuiiuws: Page 5, titres M1], 1117 and 123., eiziirus 6 7 anti 8. respeetiveiy, utter "main" insert the Wurti fuel; and that ttre'eaiti Letters Patent uiiouiti [be read] with these eurreetiurts therein that tire same may eetiiurtri te the reeurti et' tire ease in the Patent @iiiee.

igu d and seated! this 9th day ui January, it. D. i934}.

it. Mt Huuirius (Seat) Acting Cummissiuuer 011i Pateutu. 

